Cobalt is a metal that is used in numerous diverse commercial, industrial, and military applications, many of which are strategic and critical. Cobalt is used in a wide variety of applications, including:

• Batteries: Cobalt is primarily used in lithium-ion batteries, which are used in electric vehicles, tablets, and smartphones. The demand for cobalt in electric vehicles and energy storage is set to increase over the coming years.

• Alloys: Cobalt is used in the manufacture of magnetic, wear-resistant, and high-strength alloys. It is alloyed with aluminum and nickel to make particularly powerful magnets. Other alloys of cobalt are used in jet turbines and gas turbine generators, where high-temperature strength is important.

• Tool materials: Cobalt is used in the production of tool materials, such as hard alloys.

• Catalysts: Cobalt compounds are used as catalysts in the petroleum industry to refine crude oil and clean it of its sulfur content, which is very polluting when burned and causes acid rain. Cobalt acetate is used to convert xylene to terephthalic acid, the precursor of the bulk polymer polyethylene terephthalate. Cobalt compounds are also used as catalysts, desiccants, and reagents.

• Pigments: Cobalt salts have been used for centuries to produce brilliant blue colors in paint, porcelain, glass, pottery, and enamels. Cobalt silicate and cobalt(II) aluminate (cobalt blue) give a distinctive deep blue color to glass, ceramics, inks, paints, and varnishes.

• Medical applications: Cobalt-60, a radioactive isotope, is widely used in cancer treatment, as a tracer, and for radiotherapy. Cobalt is also used in external beam radiotherapy and sterilization of medical supplies and medical waste.

• Other applications: Cobalt is used in electroplating because of its attractive appearance, hardness, and resistance to corrosion. Cobalt is also an essential trace element and forms part of the active site of vitamin B12. Cobalt in inorganic form is also a micronutrient for bacteria, algae, and fungi.